With an increase of portable equipment, transportation, and communication markets, the battery industry is continually expanding to meet the increasing energy need. Typically, batteries can be broadly classified into two categories: primary batteries and secondary batteries. A primary battery, also known as a disposable battery, can be used once until the battery is depleted, after which the disposable battery can be replaced with a new battery. A secondary battery, also known as a rechargeable battery, can be capable of repeated recharging and reuse. Some advantages of rechargeable batteries are that they can be cost effective, environmentally friendly, and easier to use compared to disposable batteries.
While rechargeable batteries offer a number of advantages over disposable batteries, rechargeable batteries also have several drawbacks. Typically, battery chemistries used for rechargeable batteries tend to be less stable than battery chemistries used in disposable batteries. The relatively unstable chemistries of rechargeable batteries can require special handling during fabrication. Additionally, rechargeable batteries such as lithium-ion cell batteries have a higher risk of thermal runaway compared to cells of disposable batteries. Thermal runaway can occur when an internal reaction rate of a battery cell increases beyond a point that heat generated by the cell can be withdrawn, causing a further increase in both reaction rate and heat generation of the cell. Heat generated by a thermal runaway can lead to combustion of the battery as well as materials adjacent to the battery. Causes of thermal runaway can include: a short circuit within a battery cell, improper cell use, physical abuse of a cell or battery, over charging, internal shorts, manufacturing defects, exposure of the cell to extreme external temperatures, non-functioning safety systems, and so forth.
When a battery experiences a thermal runaway, the battery may emit a large quantity of smoke, flaming liquid electrolyte, and sufficient heat to cause combustion and destruction of materials adjacent to the cell. If a cell experiencing thermal runaway is adjacent to one or more additional cells, as can be typical in a battery pack, then the thermal runaway event can cause a thermal runaway of multiple cells which, in turn, can lead to an increase in collateral damage.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.